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Experimental
Program
An
understanding of the fundamental constituents of matter and the
forces with which they interact is sought in high energy physics
experimental programs that are performed at colliding beam accelerator
facilities of two complementary types: Hadron colliders and electron-positron
colliders. Each of these programs has a current, operating experiment
and a future experiment in either the construction phase or the
research and development phase.
The
hadron collider program is based upon the currently operating Tevatron
2 Collider and DØ experiment at Fermilab to be followed (starting
in 2007) by the CMS experiment at the CERN Large Hadron Collider
(LHC). The physics objectives of this program are to study top and
beauty physics, electroweak bosons W and Z, QCD processes, and to
search for evidence of electroweak symmetry breaking (such as Higgs
bosons or technicolor), supersymmetry, extra (hidden) spatial dimensions,
and other new phenomena. This program has provided many important
physics results over the last decade, among them the discovery of
the top quark in 1995. Notre Dame graduate students have written
dissertations in all these research areas. Additionally, Notre Dame
has been involved in the recent upgrade of the DØ detector
to magnetic tracking, being a pioneering group in the development
of scintillating-fiber tracking technology. Notre Dame manages the
operation of the Central Fiber Tracker for DØ, directs the
offline track reconstruction effort for the experiment, and is involved
in the building of an improved level-1 track trigger processor for
enhanced detector performance at increased luminosity. Fiber-optic
techniques are also critical to the operation of the CMS hadron
calorimeters at the LHC, and Notre Dame has been extensively involved
in the design and construction of key elements of the electro-optical
readout of these CMS detector subsystems, and has been engaged in
R and D on new scintillator and waveshifter materials for improved
calorimetry performance under high luminosity operation.
The
electron-positron collider program is based upon the currently operating
BaBar experiment at SLAC. This program, too has provided remarkable
physics results, notably the observation by BaBar of CP violation
in the b-quark system in 2000 - the first observation of CP violation
outside of K L decays, which were discovered in 1964. Physics goals
include systematic study of CP violating effects in a variety of
decay modes in the b-system as well as studies of rare decays of
beauty and charm mesons. Luminosity increases for the BaBar experiment
are planned, and Notre Dame is engaged in refinements of the readout
electronics of the central tracking chamber to improve track reconstruction.
A
variety of R and D projects are underway for the future Linear Collider
including, for detectors: scintillator and waveshifter development
for fast triggering, calorimetry, muon detection, and tracking;
and for accelerators: beam controls and diagnostics systems.
Theoretical
Program
In theoretical high energy physics,
refinements are pursued in the phenomenology of the standard model
as well as 'new' physics beyond the standard model, particularly supersymmetry.
This new physics can be manifested by its presence in CP asymmetries
like the one recently measured at SLAC, the first new CP measurement
in 40 years. Also being analyzed is supersymmetry and other attempts
to tie the electroweak symmetry breaking in the standard model to
a more fundamental understanding of nature, including connections
to cosmology such as the dark matter and dark energy. Baryo- and lepto-genesis
in the Universe is also studied as well as scenarios with extra space
dimensions and even multidimensional time.
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